Absorbent solution for core oven fumes



nited States This invention relates to the treatmento'f fumes from foundrly core ovens and, more particularly, to materials and formulations for removing from such fumes and the exhaust ducts through which they pass noxious, dangerous and harmfulproducts contained therein.

In conventional foundry practice, sand molds and cores used for casting sometimes have binders or bonding agents added to the sand, or other agents applied over the surface of the mold or core, which are subsequently decomposed by baking or other treatment of the mold, etc. Such bonding agents include carbohydrates, such as flour, starch derivatives, sugars, especially molasses, oils, resins and other organic materials. Since such bonded sand is most often used in cores, we shall refer here to core as representative of the various articles which may be made of such bonded sand, including molds, patterns, etc.

As these cores are passed through a core oven, decomposition of the organic materials produce by-products many of which are volatile in nature or in such finely divided solid or fog form as to be carried away with the efiluent fumes from the core oven; and these fumes also entrain fine solid particles of the core materials such as sand, resins, fillers etc., or dusts carried into the core ovens.

It has been found that many components of such core oven eflluents are hazardous or create a legal nuisance. Volatile products in the stack may present a serious explosion and fire hazard. After they condense on the inside of an exhaust stack they build up masses ofinflammable material, which increase the fire hazard. The removal of these has required expensive manual labor, and the chipping away of resinous and carbonaceous deposits has often resulted in damage to the apparatus being cleaned. The loss of operating time while apparatus is shut down for cleaning, and even more when it is shut down for repairs after damage by fire or by maintainance crews, can be a serious matter;

Additionally, such efliuents may contain odoriferous or irritating components which create unpleasant or even hazardous conditions for persons in the vicinity of the core oven exhaust, and even such of the components as are neither hazardous nor noxious may be of a corrosive character and thus may attack exhaust ducts or nearby valuable articles or structures. When deposits build up on the apparatus their removal from time to time may be very expensive, especially considering loss of production.

The amount of such materials produced in a large foundry operation is too great to merely wash out of the fumes and discharge to the sewer. It is important for such operations therefore to obtain a high efiiciency in the use of wash liquids.

As more particularly set forth in the copending application of Orlan Arnold, Dewey Evans, Willard Johnson and Emil Umbrieht Serial No. 608,365 filed September 6, 1956, such efiiuent fumes from core ovens can be treated by washing to remove therefrom objectionable byproducts and residues contained therein and the fumes aten t 2 promptly chilled to avoid fire hazard before exhausting the fumes into the atmosphere or through exhaust stacks. If conditions are "such that deposits can form on exhaust d'uct's, e'tc., from the oven or on the washing apparatus itself, they can be treated with a material which 'will re"- move them and wash them away.

This invention relates particularly to materials and formulations adapted for use in such washing to remove, solubilize, neutralize, and/or otherwise render uuobjection'able the liquid, gaseous and/or solid materials encountered in fumes from core ovens and the like.

One object of this invention is to provide formulations and materials for making washing solutions for core oven fumes adapted to solubilize, neutralize, de-odorize and/or remove objectionable components therein. 7

Another object of this invention is to provide a washingeomposition of the character described adapted to treat various materials found in core oven fumes to prevent corrosion of the apparatus thereby and condensation or build up 'of the materials on the apparatus.

A further object of this invention is to providewashing materials of the character described for treating core fumes and the like adapted to solubilize components in said fumes and/ or to digest or disperse solid or insoluble components therein forreinoval from the fumes and from the exhaust ducts in fluid solution or dispersion, so that they can be pumped and stored and flowed through pipes without clogging or expensive maintainance.

Still another object of this invention is to provide fluid washing materials of the character described for use in treatment of core oven fumes and the like-in washing apparatus of the character described and adapted 'to react with, neutralize, remove, solubilize, de odorize, and/or otherwise render unobjeetion'able a wide variety of waste products and by-products.

Other objects and advantages of this invention will be apparent from the following description-and the appended claims.

One of the diifi'culties frequently encountered in attempts to render core oven fumes unobjectionable involves the fact that the exact identity of many of the products encountered is not known with certainty, nor are many of the reactions forming such products within the core oven determined in detail. The present inven= tion is based in part on 'a study of these products, which indicates that the objectionable and hazardous products are fine soot and graphite, ash particles, corrosive acidic organic components, toxic and lachrymator components,.

and a variety of resinous and resin-forming components. The composition of core oven fumes varies considerably as the baking progresses; and as the fumes pass through duets from the ovens, various chemical reactions progress therein and various components originally in the fumes are condensed and deposited on the inner walls of the apparatus.

Many of these organic materials, formed in the oven in clude active unsaturated linkages and active monomer or low polymer groups such as aldehyd'es, acids, etc. Consequently, resinous materials are formed or further polymeiized to hard resinous deposits on the inner walls of the exhaust ducts, and some of these materials become harder and more insoluble with the passage of time, resisting mechanical and solvent removal.

Heretofore, removal of materials from such gases has been generally re arded as a dust collection or gas serub= bing operation. Aeeording to the present invention it is properly treated as a problem of chemical reaction as well as of surface-active J The Washing materials embodying this inventioninclude components roviding a wide adaptability for treat= ing, removing, and rendering unobjecti'onable these vari ou's components of core even fumes. Such ma: 7

. 3 terials include components which neutralize corrosive materials in the fumes, prevent or interfere with deposition of organic residues on the apparatus, solubilize and remove such materials as may deposit on the interior of the exhaust ducts or the fume washing apparatus, dc"- odorize the effluent fumes, convent fume components to a soluble or dispersable form for continuous removal, arrest or control undesired polymerization or chemical reaction among the constituents, prevent or control cor rosion or erosion of the ducts and/or other equipment, and eliminate fire and explosion hazards from the exhaust ducts.

Washing materials embodying this invention include an alkaline and detergent component, a defoamant component, a corrosion inhibiting component, along with solvents, etc., and may also. contain a deodorizing or odor masking component. Illustrative of various materials with which satisfactory results have been obtained in the treatment of core oven fumes with washing formu lations embodying this invention, are the following:

Geraniol (C H CH OH) Butyl propionate.

Geraniol butyrate (C H- COOC H11) Iso amyl valet-ate.

Geranyl acetate (C H C H Iso amyl salicylate.

The polypropylene glycols and polyalkylene glycol polymers referred to above are preferred as the defoamant component because such materials appear to provide a proper balance between a water phase and organic phases in a washing operation of the character described. With polypropylene glycols a molecular weight range from 2000 to 4000 is preferred, although molecular weight ranges from 1000 to 10,000 may satisfactorily be used. The polyalkylene glycol components referred to are high polymers prepared from propylene and ethylene oxides to give a polyglycol type of molecule. Polyglycol alkyl ethers, and polyglycol aromatic ethers, such as polyglycol phenyl others have proven very elfective as defoamants in washing core oven gases. Of the polyglycol alkyl ethers having a molecular weight in the range from 400 to 2000, polyglycol P-600X-octyl ether is preferred. Of the polyglycol aromatic ethers having a molecular weight in the range from 500 to 4000, polyglycol P4000 phenyl other is preferred.

As with the propylene glycol, the best materials are of no or little solubility in water, have a Saybolt viscosity in the range of 1700 seconds at 100 F. and 250 seconds at 210 F. although lower or higher viscosity materials may be used with appropriate adjustment of concentration or dilution. Also, a distinct organic solvent may or may not be required depending upon the solubility characteristics of the other components. In

formulations where an aliphatic solvent, is .used it is selected to have an open-cup flashpoint of at least above 180 F. and preferably above 200' F.

Satisfactory results have been achieved using from 20% to 99.8% of a detergent component, which may itself perform the function of the alkaline bufier component or may include from 20% to 45% of a separate alkaline A bufier, With such components, from .05% to 5% of a corrosion inhibiting component are used and from .01% to 5% of a defoamant component, depending on the specific materials included, and the material to be cleaned.

Lastly and optionally the composition includes 0.05% to 0.5% of a deodorant or odor masking component.

Illustrative washing materials embodying this inventionaud' utilizing an alkaline buffer component and a detergent component are noted within the following ranges of materials and proportions:

Alkaline butter component: Percent (Sodium carbonate, sodium bicarbonate and/or sesquicarbonate) 20 to'45 (Sodium tripolyphosphate, borax and/or tetrasodium pyrophosphate) 10 to (Trisodium phosphate) 10 to 40 Defoamant component: I

(Polypyropylene glycol) 0.1 to 5 (Silicone oil) 0.1 to 1 Corrosion inhibitor:

(Sodium and/or potassium dichromate and/or sodium and/or potassium nitrite) 0.1 to3 Aliphatic solvent 0.1 m5

Percent Sodium metasilicate 93 to 97.25 Corrosion inhibitor 0.25 to 1 Polypropylene glycol 0.25 to 5 Satisfactory results are obtained with formulations having' the above ranges of proportions and materials when the mix is added to the wash water to maintain a pH above about 8.5 while the washing system is in operation.

If less of the sodium metasilicate is desired in the range of, for example, down to 50%, a separate neutralization component may be added as, for example, sodium hydroxide in the range of 0.1% to 50%, for the desired pH control, along with 0.05% to 5% of the corrosion inhibitors and polyalkylene glycol defoamants. Satisfactory results are also obtained with the phosphate types of detergent components without a carbonate or hydroxide component as, for example, in mixtures having sodium tripolyphosphate and/or tetrasodium pyrophosphatc above about mixed with additional amounts of trisodium phosphate and the foregoing amounts of corrosion inhibiter and defoament components to give the desired pH. Sodium metasilicate and sodium tripolyphosphate may satisfactorily be intermixed as the detergent and alkaline buffer components, and satisfactory results are obtained with trisodium phosphate substituted for as much as 25% of sodium metasilicate in the above formulations. A deodorizing odor masking component may satisfactorily be added to the various foregoing formulations in amounts ranging from 0.05 to 5% thereof.

Two typical specific formulations illustrate of washing materials embodying this invention are as follows:

Formulation one:

32.6% soda ash 32.6% sodium tripolyphosphate crystalline 0.5% polypropylene glycol 32.6% trisodium phosphate crystalline 0.5 aliphatic solvent 0.1% silicone defoamant 1.0% sodium dichromate Accordingly; formulations and materials are provided for adding to the wash water used in washing the efiluent fumes from foundry core ovens, and these materials digest, solubilize, react with, or neutralize various objectionable components in such fumes to remove the components into an aqueous suspension or sludge in the Washing system or otherwise render them unobjectionable. Such suspension may then be run into a sewer or efiiuent stream or into a-lago'onfor sump etc. depending upon conditions and-limitations oncontamination.

In this specification I have shown and described a preferred embodiment of my inve ntion and various modi- *fications thereof; but it is to be understood that these are not intended to be exhaustive or limiting of the in- Y vention but, on the contrary, are given for purposes of group consisting of polypropyleneglycol, polyalkylenoglycol polymers, silicone oil, polyglycol alky ethers, polyglycol aromatic ethers, and mixtures thereof; and about 0.05% to 5% by weight of a corrosion-inhibiting component selected from the group consisting of the dichromates and nitrites of sodium and potassium and mixtures thereof.

2. A composition as recited in claim 1 in which the pH of said solution is within the range of about 7.2 to 8.5. i

3. A composition as recited in claim 1 which also in eludes about 0.05 to 0.5% by weight of an odor masking material selected from the group consisting of geraillustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner-of applying'it impractical use so that they may modify and adapt it in 'variousforms, each as maybe best suited to the We claim: 1 v 4 1. A solution for treating and, removing byproduct maten'als from foundry core oven fumes which consists conditions of a particular use.

I of an aqueous solution having a pI-l range of about 7 to 10.5 of a composition consisting essentially of about 20% to 99.8% by weight of an alkaline dispersing and deter- I gent componentselected from the group consisting of sodium tripolyphosphate, tetrasodium pyrophosphate, borax, sodium metasilicate, trisodium phosphate, sodium carbonate, sodium bicarbonate, sodium sesquicarbonate, sodium hydroxide, and mixtures thereof; about 0.01% to 5% by weight of a liquid-defoamant selected {from the niol, geraniol butyrate, geranyl acetate, butyl propionate,

iso amyl balerate iso amyl salicilate, and mixtures thereof.

References Cited in the file of this patent UNITED STATES PATENTS 491,365 Lukmann ,Feb. 7, 1893 1,944,122 Fife Jan. 16, 1934 2,035,940 Berresford Mar. 31, 1936 2,356,550 Volz Aug. 22, 1944 2,390,406, Wegst Dec. 4, 1945 2,487,576 Meyers Nov. '8, 1949 2,596,091 Benneville May 13, 1952 2,649,166 Porterct a1. Aug. 18, 1953 2,709,133 Meuly et al May 24, 1955 2,710,843 Stebleton June 14, 1955 2,739,903 9 Arnold Mar. 27, 1956 2,746,929 Wells et al May 22, 1956 FOREIGN PATENTS 7,463 Great Britain of 1837 OTHER REFERENCES Pluronics (Information), pp. 5, 9 and 10 (Mar. 1, 

1. A SOLUTION FOR TREATING AND REMOVING BY PRODUCT MATERIALS FROM FOUNDRY CORE OVEN FUMES WHICH CONSISTS OF AN AQUEOUS SOLUTION HAVING A PH RANGE OF ABOUT 7 TO 10.5 OF A COMPOSITION CONSISTING ESSENTIALLY OF ABOUT 20% TO 99.8% BY WEIGHT OF AN ALKALINE DISPERSING AND DETERGENT COMPONENT SELECTED FROM THE GROUP CONSISTING OF SODIUM TRIPOLYPHOSPHATE, TETRASODIUM PYROPHOSPHATE, BORAX, SODIUM METASILICATE, TRISODIUM PHOSPHATE, SODIUM CARBONATE, SODIUM BICARBONATE, SODIUM SESQUICARBONATE, SODIUM HYDROXIDE, AND MIXTURES THEREOF, ABOUT 0.01% TO 5% BY WEIGHT OF A LIQUID DEFOAMANT SELECTED FROM THE GROUP CONSISTING OF POLYPROPYLENE GLYCOL, POLYALKYLENE GLYCOL POLYMERS, SILICONE OIL, POLYGLYCOL ALKY ETHERS, POLYGLYCOL AROMATIC ETHERS, AND MIXTURES THEREOF, AND ABOUT 0.05% TO 5% BY WEIGHT OF A CORROSION-INHIBITING COMPONENT SELECTED FROM THE GROUP CONSISTING OF THE DICHROMATES AND NITRITES OF SODIUM AND POTASSIUM AND MIXTURES THEREOF. 